package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCDemo7 {
    public static void main(String[] args)  {
        try (Connection connection = DBUtil.getConnection();){

            Statement statement = connection.createStatement();
            String sql = "SELECT COUNT(*) count" +
                    "FROM class c " +
                    "JOIN student s ON s.class_id = c.id " +
                    "WHERE c.name = '1年级1班'";
            ResultSet rs = statement.executeQuery(sql);
            if (rs.next()) {
                int count = rs.getInt("count");
                System.out.println("共有"+count+"人");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}
